1. Field of the Invention
This invention relates to a milling apparatus for forming a key bit, and more particularly to a milling apparatus which can prevent metal waste from flying out of the milling apparatus.
2. Description of the Related Art
Referring to FIGS. 1 to 3, a conventional milling apparatus for forming a key bit 1 is shown to include a base 11, a carrier 12 mounted movably on the base 11, and a hollow body 13 which is fixed on the carrier 12. The hollow body 13 has an interior chamber 130, in which a milling cutter 14 is mounted rotatably. A waste collector 15 is coupled with the hollow body 13 to suck metal waste created in the interior chamber 130 in the hollow body 13. A key holding member 16 is positioned in front of the base 11, and has an upper clamping plate 161 and a lower clamping plate 162, which are adapted to clamp a key blank 2 therebetween. Two opposed pushing merrbers 131 are provided on the hollow body 13, and are biased respectively by two comoression springs 132 to press against the upper and lower clamping plates 161, 162.
In operation, the carrier 12 is moved on the base 11 from the position shown in FIG. 1 to that in FIG. 2, thereby pressing the pushing members 131 against the key holding member 16. Then, the hollow body 13 is moved from the position indicated by solid lines in FIG. 3 to that indicated by phantom lines in FIG. 3 to form a specific-shaped key bit on the key blank 2. As best shown in FIG. 3, during the milling process, a clearance 17 is formed between the hollow body 13 and the key holding member 16. As a result, metal waste created from the key blank 2 fly out of the apparatus via the clearance 17, and cannot be sucked entirely into the waste collector 15. Furthermore, as illustrated, one of the pushing members 131 may separate from the key holding member 16, thereby affecting adversely the quality of the product and even damaging the milling cutter 14.